Dentist drill control



July 6,1943} H. R. CLAUSEN 2,323,645

DENTIST DRILL CONTROL Filed Oct. 21, 1940 ELJ 73' ii h 2 '76 63 /9 I I 36 I I I I as w v v v r vz I a] v 114 K 99 I 1 5 37 I INVENTOR.

I I I I I I I I I I I I I I I l I I Patented July 6, 1943 DENTIST DRILL CONTROL Harry R. Clausen, Chicago, Ill.

Application October 21, 1940, Serial No. 362,031

Claims.

This invention relates to a surgicaLcontrol device and more particularly to a device for controlling a dental drill unit..

It is an object .of this invention to provide a surgical control device by which the surgeon or dentist in manipulating the surgical tool or appliance to perform the surgery may have positive finger-tip control of the tool or appliance.

Another object of the invention is to provide surgical tools, more particularly dentists drills, with acontrol device which enables the surgeon or dentist'tocontrol by movement of his hands along or about the tool the operation of the tool itself.

More specifically, it is .an object of this invention to provide a control device which enables the dentist, by a movement of the finger grasping his mirror or the hand piece of his drill, to control the operation of his drill.

Dental equipment now in use includes a foot switch which is used by the dentist to start and stop the motor of his drill, In working, a dentist must therefore-maintain or support a large part.

of his weight upon one leg so that he may keep the other leg substantially free for instantaneous operation of the foot switch. This is both uncomfortable andat the same time, over a long period, detrimental to the health of a dentist.-

.It istherefore a further object of this invention to provide a dentist's drill with a control which permits the dentist to stand normally on his two feet and by means of his hands control the instantaneous starting and stopping of the drill without releasing the drill from his hand.

A further object of the invention is to provide a dental drill having a currentless control incorporated in the drill by which without danger of shock to himself or to the patient, the dentist may by movement of his hand or a finger and without releasing the tool, and stopping of the drill.

Other and further objects and advantages of the invention will be apparent from the following description when taken in connection with the accompanying drawing, wherein:

Figure 1 is a diagrammatic view in elevation of a dental unit embodying the present invention; Figure 2 is a view in perspective of a. dental mirror forming a part of the present invention;

Figure 3 is a view in perspective of a dental drill hand piece forming a part of the invention; Figure 4 is a view in perspective of a contra angle attachment for a dental hand piece and illustrates the manner of adapting the contra angle to the present invention; and

control the starting Figure 5 is a schematic circuit diagram of a control device forming partof the present invention;

As shown in the drawing, the invention comprises a remotely controlled, control unit 2, anv

electrically operated or motor driven, surgical tool driving unit 4 controlled by the unit 2 and surgical hand tool remote controllers 6 and 8.

The control unit 2 preferably comprises a cabinet or housing It in which is mounted a thermionic vacuum tube l2 having a filament 14, a cathode ii, a control grid l8, a screen grid 20 and a plate or anode 22.

A cable 24 connects the control unit 2 to the electric. operator or motor 28 of the surgical tool driving unit 4 and to the supply lines L-I and .L-2. In the modern dental unit the supply lines are housed within the stand 28 of the unit and therefore the cable 24 extend from the control unit 2 into the stand 28 where the connections are made to the motor 26 and the power supp y lines. The'conventional foot switch" 88, which may be provided or retained as a presettable speed control and master switch, is connected to the motor and supply lines through a cable 32 extending into the stand 28.

Current is supplied to the filament l4 of the tube l2 from supply line L--i through wire 34 of cable 24, wire 35 of the control unit, resistor or ballast tube 86, filament I4, wire 31,- control switch 38, wire 48, and wire 42 of the cable 24 to the supply line L-2. One side of the filament is connected to the cathode It by the wire 43 and to the control grid l8 through a resistor 44 and an air core choke coil or inductance 46.

A low voltage pilot lamp 48 is connected across a portion of the resistor 36'and serves to indicate the operative condition of the control unit. The pilot lamp 48 and the control switch 38 are mounted on the face of the cabinet Ill of the control unit which is positioned within easy reach and constant observation of the dentist as he is working.

The plate or anode 22 is connected to the power lead 35 through wire 52; resistor 54, wire 58, air core choke coil or inductance 58 and wire 60. The coils 48 and 58 are adjustably related so that the mutual inductance between the coils may be varied to cause the tube circuit to oscillate at a high frequency or to vary the value of the high frequency oscillating current within the circuit. The coils 46 and 58 constitute an adjustable feed backtransformer coupling the plate circuit to the control grid circuit. Relays 6| and 82 have their coils 63 and 84 connected in series across the resistor 54 by the wire 56 and a wire 66. A by-pass condenser 68 is also connected in shunt to the resistor 54 and a tuning condenser 10 is connected in shunt to the coil 58.

The switch of the relay 6| comprises a single pole double throw switch blade 12 and contacts 14 and 16. The contact 14 is connected to the supply line L-I through the wire 13 of the control unit, the wire 80 of the cable 24, the wire BI of the cable 32, the master switch blade 82 of the foot switch 30, the wire 03 of the cable 32, the wire 84, the motor commutator or rings and armature, the wire 85, the wire 66 of the cable 32, the wiper blade 01 of the adjustable resistor 88 in the "foot switch 30, the wire 99 of the cable 32, the wire 90, the stator coils of the motor 26, and'the wire 9I to the line L-I. The switch blade 12 is connected to the supply line I.r-2 through the wire 92 of the control unit and the wire 93 of the cable 24.

The relay 62 is a single pole, single throw, normally open time delay relay. The contact 94 of this relay is connected by the wire 95 to the contact 16 of the relay 6I, the contact 16 being engaged by the blade 12 when the coil 63 is, in eflect, deenergized. The switch blade 96 of the relay 62 is connected to the stator coils of the motor through resistor 96, wire 99, and wire I of cable 24 to wire 90 and is urged into engagement with the contact 94 when the coil 64 is, in effect, deenergized. A protective condenser I0! and resistor I02 are connected in series and across the switch blade 12 and contact 14 so that in breaking the circuit to the motor, no arc will be established between the blade 12 and the contact 14.

A surgical hand tool remote controller 6 comprises a dental mirror I03 having the usual cylindrical shank I04 of electrical insulating material such as Lucite which permits light to be directed through the shank onto the disc mirror. A small wire I05 extends through the center of the shank I04 and is connected at its inner end to a small electrically conducting, preferably copper, button, strip or contact piece I06 set into the surface of the shank and exposed so that the dentist may conveniently engage it with one of his fingers as he manipulates the mirror. At the upper free end of the mirror shank, the wire IE5 is provided with a projecting contact pin or plug I01 adapted to receive a clip or contact cap I08 secured to one end of a fine wire I09 which may be provided with the usual insulating coating or covering. The wire I09 is plugged into the control unit 2 in which it is connected to one side of a blocking condenser I [2. The other side of this condenser is connected by the wire II4 to the cathode end of the coil 46.

The surgical hand tool remote controller 0 comprises a dental drill hand piece I I6, the steel sheath I20 oi which is provided with a longi tudinal groove having seated therein a fine insulated wire I22. The wire I22 at its lower end is connected to a small electrically conducting, preferably copper, button, strip or contact I24. The contact button I24 is mounted in a surface groove in the steel sheath I20 from which it is insulated as by the insulating coating or strip I26. The surface of the contact button I24 is exposed so that the dentist may conveniently engage the button with one of his fingers while holding the hand piece H8. The wire I22 at its upper end engages a conducting ring I20 mounted on, but insulated from, the steel sheath I20 just beneath the conventional operating and mounting head I30 of the hand piece 110. It may be noted in respect to this operating and mounting head that it includes the mounting bracket I32 and a driven pulley I34 which through the spindle of the hand piece drives the drill or other surgical instrument I35. The ring I23 is connected to a fine, insulated wire I36 which is plugged into the control unit 2 in which it is connected to the condenser II2.

Figure 4 illustrates the manner in which the contra angle attachment I38 for the hand piece II6 may be equipped with an extension for the contact button I24 so that when the contra angle is employed, the control may readily be operated by the dentist with his fingers in the normal position in which he usually grasps the contra angle in use. Thus the contra angle I36 has attached thereto an insulated contact strip I40, 9. portion of the insulation of the strip being removed adjacent its lower end to expose a contact button I42. The insulation of the strip I40 is also removed from its lower surface adjacent its upper end so that when the contra angle is slipped over the lower end of the hand piece I II, this exposed part engages and makes electrical contact with the contact button I24.

The right angle hand piece attachment which is generally similar to the contra angle attachment I38, may in a similar manner be provided with an insulated strip such as I40 for the same purpose.

The inductive relation between the coils 46 and 58 'may be varied by operation of the knob I44 secured to the adjusting shaft of these coils exteriorily of the cabinet or housing I0. The coils 46 and 58 may be mounted in any conventional manner providing a stationary support for one of the coils and an adjustable mounting for the other of the coils, the adjustable mounting being of course connected to the' shaft which carries the operating knob I44. The control unit 2 may be mounted in any desirable convenient location, preferably adjacent to, .on, or within, the stand 28. As shown in Figure 1, this control unit is mounted on the arm or bracket I46 which supports the tray and accessory table unit I48. The control unit may, however, be built directly into the stand 28 as will be apparent.

In operation the coils 46 and 5B are relatively adjusted so that the plate current through the relay coil 63 is suiiicient to hold the relay switch blade 12 in its lowermost position engaging contact 16 and the motor 26 is deenergized.

When a surgeon or dentist presses his finger upon a contact button I06, I24 or I42, the current in the thermionic tube, high frequency oscillating or capacity controlled circuit decreases to such a value that the plate current to the relay coil 63 becomes insufficient to hold the blade 12 in contact with the contact 16 and the springimpelled relay switch blade 12 moves into engagement with the contact 14. This completes a circuit to the motor 26 from the supply line L-I through the wire 9|, the stator coils of the motor 26, the wire 90, the wire 99, the resistor 88 and wiper 81 of the foot switch 30, the wire 86, the wire 85, the armature oi the motor 26, the wire 84, the wire 63, the master switch 02 of foot switch" 30, the wire al, the wire 80, the wire 18, the contact 14 and blade 12 of relay 6| the wire 92 and wire 93 to supply line L-2. The motor 26 therefore is now energized and drives the drill or other surgical instrument I 35. As soon as the dentist raises his finger from engagement with the contact button I06, I24, or I42,

the current in the thermionic tube oscillating circuit increases instantaneously and the blade I2 snaps to its normal position, engaging contact.

16. The circuit to the motor 20 is broken as soon as the switch blade I2 leaves the contact I4. When the blade I2 engages the mntact 10, the circuit is completed to the stator coils of the motor through the resistor 08 while the armature is deenergized thereby to dynamically brake the motor so that the motor very quickly comes to rest. This circuit is completed from the line LI through the wire the stator coils, the wires 90, I00 and 80, the resistor 98, switch blade 96, the contact 00, .the wire 95, the switch contact I6, the blade 12 and wires 02 and 90 to the supply line L-2. when the current becomes suflicient to operate relay 0|, it also operates relay 62 to move its switch blade at out the operation of the drill be not initiated until it is brought into the cavity'or into -iuxtaposition to the tooth to be drilled. It is also deslrable for the further positive protection of the patient against inadvertent cutting by the instrument or drill, that it be automatically stopped while being withdrawn or'when the surgeon or dentist moves away from the patient.

In such cases, the coils l6 and I0 may be admay be established through that one of the supply lines which is always grounded.

For the purpose of illustrating the invention, the same has been shown as embodied in a dentist's equipment for the control oi the operating motor of the dentist's hand drill. However, it will be apparent that theinvention may be embodied in other surgical equipment, including other surgical hand tools, so that th operation of tools may be maintained under the control of the hand which holds the tool. Thus, for example, the remote controlling unlt may comprise a chiropodists cutter tool in which there is provided a small copper electrically conducting button, strip orcontact piece similar to the contact button I and similarly mounted on the hand piece of the cutter so that through the control unit 2, the electric cutter drive mechanism or the contact button of the hand tool, nor does any justed relatively so that the oscillating current,

when the button I00, I24, or I42 is engaged, is not reduced sufficiently to release the relay 6|, but when the dentist places one of his hands near or in contact with the patient as when he places the mirror or drill in the patient's mouth, the cifi'rent of the oscillating circuit becomes suill- ,ciently reduced to release the relay II and energize the motor 28. If the drill bit should become stuck in the patient's tooth so that it could not be withdrawn quickly, the drill motor may still be deenergized by the dentist by simply removing his finger from thecontact button I 06, I24,

or I42.

In some cases as when using the mirror in drilling operations it becomes desirable to have the control exercised through the hand holding the mirror, rather than through the hand holding the drill hand piece. In such case, only the wire I00 of mirror controlling unit 6 need be plugged into the control unit 2 to determine the operation of the oscillating circuit and'determine the operation of the motor 28.

The coils l6 and 50 may be so adjusted relatively that an increase or decrease in the pressure with which the contact button is engaged will cause a starting or stopping of the motor, and therefore the control may be eifected without actually disengaging the contact button.

By physical engagement of the contact button by the surgeon or dentist, or by increase in the pressure of the engagement, the capacity to ground from the coil 46 is varied to cause the circuit to stop oscillating or oscillate feebly. Any suitable part of the oscillating circuit may be directly connected to ground. For example, the cathode It may be directly grounded by the wire I02 (Figure 5), or suitable ground connectionmeasurable voltage, capable of providing an electric shock, exist between. the contact button and ground, and hence the tools may be handled with absolute safety and in the same manner as formerly.

For illustrative purposes, it may be stated that in a particular case. the oscillating circuit embodied a thermionic tube known as "25 156T," and the impedances of the circuit had the following values:

Coil 40, 16 millihenries;

Coil 50, 8 millihenries;

Condenser ll, 10 microfarads;

Condenser I0, '.0002 microfarad; v

Condenser IN, 1 microfarad;

Condenser I I2, .003 microfarad;

Resistor 36 was a ballast tube providing a 92 volt drop at the rated filament current of the tube I2;

. Resistor 44 was oi Y4 mezohm;

Obviously, the invention is not limited to the specific disclosure herein but is capable of other modifications and changes without departing from the spirit and scope of the appended claims.

The invention is hereby claimed as follows:

1. A surgical device comprising a driven surgical instrument, an electric motor for driving said instrument, a relay controlling the energization of said motor, a high frequency oscillation generating circuit controlling said relay, a surgical hand tool having an exposed electrically conducting member connected to said oscillation generating circuit and positioned for engagement by the operator's hand while holding the tool to control said oscillation generating circuit whereby to control saidrelay, and a circuit completed by said relay upon deenergizing of said motor for dynamically braking said motor.

2. A surgical appliance comprising a member having a shank adapted to be grasped in the hand, an electric conducting member embedded in the shank of the tool and electrically exposed for engagement by the hand while grasping the appliance and electric conductor means insulated in the shank of the appliance but extending outwardly therefrom for connection to a capacity responsive control unit of an electrically driven surgical instrument.

3. An electrically driven surgical cutter comprising a cutter receiving member having a shank adapted to be grasped in the hand, an electrically conducting member having a portion embedded in the shank and electrically exposed for engagement by a finger oi the hand grasping the shank, and means for connecting said electrically conducting member to a capacity responsive control unit adapted to control the electrically driven surgical cutter.

4. A dental device comprising a drill receiving hand tool, a motor for driving the drill, a foot control including presettable means connected to said motor for controlling the speed of said motor, a relay connected to said motor and said foot control for' energizing and deenergizing said motor and said foot control, a capacity responsive high frequency oscillation generating circuit connected to said relay, said hand tool having a shank, variable capacity control means for said oscillating circuit, said variable capacity control means comprising electrically conducting means a time delay relay controlled by said oscillation generating circuit and connected to said flrst relay and said motor for establishing a dynamic braking circuit through the motor upon deenergization of said motor by the first relay and automatically opening said dynamic braking circuit upon the lapse of a predetermined time.

5.'A dental device comprising a dental drill, said drill having a shank adapted to be grasped in the hand, an electrically conducting member embedded in the shank and having a portion exposed for engagement bythe hand while grasping the shank, and a contra-angle attachment for said drill, said attachment having an insulated,. electrically conducting member fixed thereto and adapted to extend therefrom longitudinally of the drill shank, a portion or said member being exposed for engagement with the electrically exposed portion of the electrically conducting member embedded in the shank of the drill and having a second exposed part for engagement by the hand while grasping the drill with the contra-angle attachment secured thereto.

HARRY R. CLAUSEN. 

